Sexual compatibility types of Bremia lactucae isolates originating from Lactuca serriola

Results are given on the occurrence of sexual compatibility types of seven isolates ofBremia lactucae originating fromLactuca serriola (prickly lettuce). It is concluded that the isolates studied are heterothallic. Both compatibility types (B1 en B2) were determined, but type B2 was prevalent. Sexual recombination ofB. lactucae isolates originating from wild and cultivated lettuce may occur.Samenvatting Zeven isolaten vanBremia lactucae, afkomstig vanLactuca serriola in Tsjechoslowakije, zijn onderzocht op hun sexuele compatibiliteitstype door ze te combineren met Nederlandse fysio's vanB. lactucae, afkomstig van cultuursla (L. sativa), waarvan het compatibiliteitstype (B1 of B2) bekend is. Alle isolaten vanL. serriola bleken heterothallisch te zijn, waarbij type B2 meer werd aangetroffen dan type B1. Sexuele recombinatie vanBremia-isolaten van wildeLactuca-soorten en cultuursla blijkt goed mogelijk te zijn.     

Concepts and Direction of Induced Systemic Resistance in Plants and its Application

Resistance to plant disease is often specific and metabolites and receptors contributing to this specificity may have specific structures. However, simple, structurally-unrelated compounds induce systemic resistance in unrelated plants to diverse pathogens including fungi, bacteria and viruses. Both resistance and induced systemic resistance (ISR) are associated with the rapid accumulation of the same structurally unrelated putative defense compounds that have diverse functions. It has been suggested that cultivar (race)-specific resistance is initiated by the specific interaction of a pathogen product (or pathogen induced product) and a plant receptor. However, restricted infection by pathogens can result in ISR and many different compounds can cause ISR. It is thus evident that there are both specific and non-specific routes to the master switch for ISR and there may be more than one master switch. Are reactive oxygen species and free radicals regulating the master switch(es) via both routes? It is also evident there are many switches, other than the master switch. Adding to the complexity of resistance and ISR are the observations that different compounds and pathways may mediate different biochemical resistances. Activation of one of the pathways may antagonize or enhance the activation or effectiveness of another. The review will address these complexities and questions and propose directions of research which require high priority. Factors which encourage and suppress the application of ISR in agriculture will also be addressed.     

Fate of humic acids isolated from natural humic substances

Composition of humic acids (HA) is a function of plant-derived inputs, degradation processes regulated by microorganisms, organo-mineral interactions and age. Characterization of different origin humic substances is important for evaluation of their contribution to stabile and labile carbon pool in the environment. The relative abundance of chemical components in HA isolated from soils, compost, commercial lignohumates, alginite, acadiane and lignite was studied with aim to quantify content of important biomarkers such as amino acid, lipids and polyphenols. HA were considered as a heterogeneous complex and high concentration of peptides, polyphenols and lipids was determined in acadian-HA to compare with soil-HA. Compost-HA contained much more amino acids to compare with soil-HA samples. Alginite-HA and lignite-HA were similar in biomarkers content to soil-HA. Fourier transform infrared spectroscopy confirmed that chemical composition and functional groups content differs with the origin, humification degree and the age of studied samples. Soil-HA are typically composed of a variety of ?OH, COOH?, C–O, C–H₂, (aliphatic and aromatic) groups, quinines, lignin fragments, polysaccharide, monosaccharide and proteins fragments, which are linked together by ?O?, ?NH?, ?H=, >C=O, metal ions and –S? groups. ¹³C NMR spectroscopy showed that aromatic carbon content was the highest in lignite-HA and soil-HA.     

Gill Reaction to Pollutants from the Tamiš River in Three Freshwater Fish Species,Esox lucius L. 1758, Sander lucioperca (L. 1758) and Silurus glanis L. 1758: A Comparative Study

The study evaluated the effects of waterborne pollutants from the Tami? River on gill histology and possible differences in gill reaction patterns between three freshwater fish species, pike Esox lucius L. 1758, pike‐perch Sander lucioperca (L. 1758) and wels catfish Silurus glanis L. 1758 from the Tami? River. Gills from analysed fish species showed moderate to intense histopathological alterations. The most frequent progressive alteration was hyperplasia of epithelium, whereas the most frequent regressive alteration was epithelial lifting. Circulatory disturbances were most often manifested in the form of hyperaemia. During comparative analysis, differences in gill indices, reaction and alteration indices, as well as in gill and filament prevalence between analysed species, were observed. Although all analysed fish species did show both progressive and regressive alterations, there was a significant difference in the level of expression of these reaction patterns. Gill index obtained for pike clearly stands out as the lowest. Wels catfish showed the highest progressive reaction index, significantly higher in comparison with the other two species (P < 0.05), while pike‐perch showed the highest regressive reaction index, also significantly higher in comparison with the other species (P < 0.001). These results may implicate species‐specific gill reactions and thus present a useful tool for better understanding toxic mechanisms of various pollutants.     

Morphological examination of the intraorbital muscles (musculi bulbi) in dogs in the perinatal period

Twelve American Staffordshire terriers, gestational day 60, and 10 dogs de Bordeaux, gestational day 57 were examined in respect of the morphology and morphometry of their intraorbital muscles. The location of the retractor bulbi, recti and oblique muscles was described and the length of the muscles, the length and breadth of their tendons as well as the distance of the distal insertions of the muscle tendons from the corneal limbus were measured. Similarly, the shape of the line of distal insertions was investigated. The measurements were taken with an electronic caliper to the nearest 0.1 mm. The distance insertion-corneal limbus was measured by means of the Hifny and Misk method (1982). The following differences between the breeds in the morphometry of the intraorbital muscles and their tendons were found out. The distal insertions of the tendons of the dorsal, ventral and lateral recti muscles are further from the corneal limbus in American Staffordshire terriers than in dogs de Bordeaux. The muscular funiculi of the retractor bulbi muscle are further from the corneal limbus in dogs de Bordeaux, except the dorsolateral funiculus (1.96/1.94 mm). In addition, there are differences in the morphometry of the intraorbital muscles and their tendons. No differences, however, were found in the morphology of the intraorbital muscle tendons (their insertion line) and their location. The study can be applied to clinical sciences (surgery) and veterinary ophthalmology, in particular.     

Flowering estimation in apple orchards by image analysis

Tree-specific management practice related to individual tree physiological condition is necessary for higher quality and quantity in apple fruit production. Detection of apple flowering abundance based on analysis of HSL (hue, saturation, luminance) images was used to estimate the number of flower clusters (FC) of individual trees in a high density apple orchard. The image acquisition was performed with a still camera and an industrial color camera during the day and night. The FC estimation algorithm included HSL thresholding with parameter optimization. Three hypothetical, tree-specific management practices (sprayings) were assumed, using >25, >50 and >100 FC thresholds to carry out the practice. When an industrial camera was used for image acquisition during the daytime and hypothetical spraying was done by on/off criterion >100 FC per tree, 10 % incorrect executions were identified. Comparable FC counting performance was achieved by using a still camera or an industrial camera.     

毛白杨植物络合素合酶(PtPCS)基因克隆及其表达研究

植物络合素(PCs)是植物细胞中一类螯合重金属离子的多肽,对细胞解毒和重金属的富集有重要的作用。植物络合素合酶(PCS)是合成PCs途径中的关键酶。本研究克隆了毛白杨的植物络合素合酶基因PtPCS,该基因cDNA序列全长1512bp,可编码503个氨基酸;与其它8种植物同源基因比对显示,它们的氨基酸序列相似性在67%～74.1%之间;构建进化树发现,这9种植物明显的分为两大分支,并且两大分支PCS蛋白的高级结构显示出明显的差异,一种呈月牙状,一种为伞状,重金属超富集植物均为月牙状结构。对毛白杨在不同镉浓度处理下PtPCS基因的表达情况分析发现,毛白杨根、茎、叶中PtPCS基因均表现出先升高后缓慢降低的表达趋势,并且在同一镉浓度处理下,毛白杨不同器官PtPCS基因的表达具有规律性,即根表达量最强,茎次之,叶片最弱。研究结果不仅为植物育种提供了重要的基因资源,也为剖析毛白杨的镉抗性和富集特性的研究奠定了良好的基础。     

Soil chemical properties,plant species composition,herbage quality,production and nutrient uptake of an alluvial meadow after 45 years of N,P and K application

Little is known about the long-term effects of mineral N, P and K application on the nutritional status of mown alluvial grasslands. We asked how long-term fertilizer application affected soil chemical properties, plant species composition, herbage production, nutrient concentrations in soils and plants and balance of nutrients. Six treatments (control, PK, N50PK, N100PK, N150PK and N200PK) were investigated at the Černíkovice Experiment (Czech Republic) established in 1966 on an Alopecurus pratensis meadow, using annual application rates of 50, 100, 150 and 200 kg N, 40 kg P and 100 kg K ha⁻¹. Data were collected and analysed for 2007, 2008 and 2009. Although fertilizers had been applied over 45 years, differences in soil chemical properties between fertilization treatments were small. The legumes Lathyrus pratensis and Trifolium repens responded highly positively to PK application, and tall grasses, A. pratensis in particular, to NPK application. Herbage quality was high in terms of content of major nutrients, and its chemical properties varied considerably between treatments, cuts and years. Mean annual herbage yield ranged from 6·1 in the control to 9·7 t ha⁻¹ in the N200PK treatment. Herbage production was N-limited in 2007 and 2009, but not in 2008. Seasonal N agronomical efficiency ranged from 4·2 to 22·9 kg of DM herbage per kg of applied N. The herbage N:P and N:K ratios did not reflect the actual response of herbage production to N application. A negative balance between N applied and N removed in harvested herbage was recorded in all treatments. We concluded that in highly productive alluvial grasslands, mineral-rich soils can respond weakly to N, P and K application, fertilizer application modifies plant species composition and herbage production is not N-limited in all years. Nutrient ratios must be interpreted with caution for the estimation of nutrient limitation.     

The impact of dry and wet cleaning on fabric electromagnetic field shield effect

The aim of this research is to investigate shield effect properties of the fabrics with inox yarns included in the construction, which are used for special professional garments and should protect from electromagnetic microwave irradiation. The investigation was done prior to and after the professional care procedures of dry and wet cleaning in ten cleaning cycles. Shield effect measurements were done on the face and on the back of the fabric, weftwise and warpwise, prior to and after the first, third, fifth, seventh and tenth cycles of dry and wet cleaning, at the frequencies from 0.9 to 2.4 GHz. The results obtained indicated that shield effect of the fabric tested was reduced after professional care procedures, especially so after 5 cycles. The investigations also revealed that shield effect could be considerably enhanced if the inox yarns were incorporated into the fabric in the direction of the warp.